1. Field of the Invention
The present invention relates generally to a valve, and more particularly to a spherical valve.
2. Description of Related Art
As shown in FIG. 1, a prior art spherical valve 40 has a tubular body 41 which is provided in the interior with a threaded portion 42, a rotary shaft 1, a ball 2, a washer 3, and an annular lock member 43. The spherical valve 40 is defective in design because it is fastened to a pipe in a specific direction, and because it cannot be easily detached from the pipe for maintenance work. As shown in FIG. 2, another prior art ball valve 50 has a tubular body 51 which is provided in the interior thereof with a threaded port 52, a rotary shaft 1, a ball 2, and a washer 3. A threaded tubular member 53 is fastened to the threaded port 52. As compared with the prior art spherical valve 40, the prior art ball valve 50 can be fastened to a pipe with a relative ease. However, the ball valve 50 cannot be easily maintained or replaced. As shown in FIG. 3, a flanged ball valve 60 of the prior art is formed of a primary tubular member 61 and a secondary tubular member 62, which make the repairing and the replacing of the flanged ball valve 60 rather complicated and time-consuming. As shown in FIG. 4, a three-piece ball valve 70 of the prior art has a main body 71, which is fastened to a pipe by two auxiliary valve tubes 72 and is unfastened the pipe between the two auxiliary valve tubes 72, thereby making the assembly work cumbersome. In addition, the ball valve 70 is complicated in construction and is expensive.